// bresenham_counter.hpp
/*
 *  Copyright (c) 2007 Leigh Johnston.
 *
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are
 *  met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 *     * Neither the name of Leigh Johnston nor the names of any
 *       other contributors to this software may be used to endorse or
 *       promote products derived from this software without specific prior
 *       written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 *  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 *  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 *  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 *  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 *  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#pragma once

#include "neolib.hpp"

namespace neolib 
{
    template <typename T>
    class bresenham_counter
    {
        /* operator T() returns x[0..N-1] = 0 .. R, i.e. x[n] = (R / (N-1)) * n, without
        using floating point or multiplication/division each iteration */
    public:
        bresenham_counter() {}
        bresenham_counter(T range, T number) : 
            dx(number-1), 
            dy(dx > 0 ? range % dx : 0), 
            d(2*dy - dx), incrE(2*dy), incrNE(2*(dy-dx)), 
            incrCounter(dx > 0 ? range / dx : 0), 
            incrCounterPlus1(dx > 0 ? incrCounter+1 : 0),
            counter(0) {}
        bresenham_counter(T rangeStart, T rangeEnd, T number) : 
            dx(number-1), 
            dy(dx > 0 ? rangeEnd > rangeStart ? 
                (rangeEnd - rangeStart) % dx : (rangeStart - rangeEnd) % dx : 0), 
            d(2*dy - dx), incrE(2*dy), incrNE(2*(dy-dx)), 
            incrCounter(dx > 0 ? (rangeEnd - rangeStart) / dx : 0), 
            incrCounterPlus1(dx > 0 ? rangeEnd > rangeStart ? 
                incrCounter+1 : incrCounter-1 : 0),
            counter(rangeStart) {}
        void init(T range, T number)
        {
            dx = number-1; 
            dy = dx > 0 ? range % dx : 0; 
            d = 2*dy - dx;
            incrE = 2*dy;
            incrNE = 2*(dy-dx); 
            incrCounter = dx > 0 ? range / dx : 0; 
            incrCounterPlus1 = dx > 0 ? incrCounter+1 : 0;
            counter = 0;
        }
        void init(T rangeStart, T rangeEnd, T number)
        {
            dx = number-1;
            dy = dx > 0 ? rangeEnd > rangeStart ? 
                (rangeEnd - rangeStart) % dx : (rangeStart - rangeEnd) % dx : 0;
            d = 2*dy - dx;
            incrE = 2*dy;
            incrNE = 2*(dy-dx);
            incrCounter = dx > 0 ? (rangeEnd - rangeStart) / dx : 0;
            incrCounterPlus1 = dx > 0 ? rangeEnd > rangeStart ? 
                incrCounter+1 : incrCounter-1 : 0;
            counter = rangeStart;
        }
        operator T()
        {
            if (d <= 0)
            {
                d += incrE;
                T v = counter;
                counter += incrCounter;
                return v;
            }
            else
            {
                d += incrNE;
                T v = counter;
                counter += incrCounterPlus1;
                return v;
            }
        }
        T operator()()
        {
            return operator T();
        }
    private:
        T dx, dy, d, incrE, incrNE;
        T incrCounter;
        T incrCounterPlus1;
        T counter;
    };

    template <typename T>
    class bresenham_counter_alt
    {
        /* operator T() returns x[0..N-1] = 0 .. R, i.e. x[n] = (R / (N-1)) * n, without
        using floating point or multiplication/division each iteration */
    public:
        bresenham_counter_alt() {}
        bresenham_counter_alt(T range, T number) : 
            n(number-1),
            partInt(n > 0 ? range / n : 0),
            partFract(n > 0 ? range % n : 0), 
            e(0),
            incrCounter(partInt),
            incrCounterPlus1(n > 0 ? incrCounter+1 : 0),
            counter(0) {}
        bresenham_counter_alt(T rangeStart, T rangeEnd, T number) : 
            n(number-1),
            partInt(n > 0 ? rangeEnd > rangeStart ? 
                (rangeEnd - rangeStart) / n : (rangeStart - rangeEnd) / n : 0),
            partFract(n > 0 ? rangeEnd > rangeStart ?
                (rangeEnd - rangeStart) % n : (rangeStart - rangeEnd) % n: 0), 
            e(0),
            incrCounter(rangeEnd > rangeStart ? partInt : -partInt),
            incrCounterPlus1(n > 0 ? rangeEnd > rangeStart ? incrCounter+1 : incrCounter-1 : 0),
            counter(rangeStart) {}
        void init(T range, T number)
        {
            n = number-1;
            partInt = n > 0 ? range / n : 0;
            partFract = n > 0 ? range % n : 0;
            e = 0;
            incrCounter = partInt;
            incrCounterPlus1 = n > 0 ? incrCounter+1 : 0;
            counter = 0;
        }
        void init(T rangeStart, T rangeEnd, T number)
        {
            n = number-1;
            partInt = n > 0 ? rangeEnd > rangeStart ? 
                (rangeEnd - rangeStart) / n : (rangeStart - rangeEnd) / n : 0;
            partFract = n > 0 ? rangeEnd > rangeStart ?
                (rangeEnd - rangeStart) % n : (rangeStart - rangeEnd) % n: 0;
            e = 0;
            incrCounter = rangeEnd > rangeStart ? partInt : -partInt;
            incrCounterPlus1 = n > 0 ? rangeEnd > rangeStart ? incrCounter+1 : incrCounter-1 : 0;
            counter = rangeStart;
        }
        operator T()
        {
            e += partFract;
            if (e < n)
            {
                T v = counter;
                counter += incrCounter;
                return v;
            }
            else
            {
                e -= n;
                T v = counter;
                counter += incrCounterPlus1;
                return v;
            }
        }
        T operator()()
        {
            return operator T();
        }
    private:
        T n, partInt, partFract, e;
        T incrCounter;
        T incrCounterPlus1;
        T counter;
    };
}
